For various medical procedures it is necessary to dispense a liquid composition from a reservoir via a tube to a patient or to transfer a composition from a patient to a reservoir via a tube. Examples involving such procedures include the administration of saline solutions from a reservoir to a patient, the continuous collection of urine for analysis in a pouch reservoir and the administration of a barium enema prior to radiography from an enema bag.
The specialized reservoirs used for administration of solutions and suspensions have in common that they are provided with at least one integral delivery tube or means for connection to a delivery tube. Usually they have been provided in addition with a filling port and have been made from glass, rubber, PVC and even metal according to administration requirements. The reservoirs and associated fittings are manufactured in many forms and sizes each adapted to serve a particular function. Some are part of highly specialized apparatus. Others are simple PVC or polyethylene bags with integral tubular fittings.
The compositions administered are liquids which term as herein used includes solutions suspensions and emulsions. Traditionally the compositions were made up immediately prior to use although nowadays many of the required compositions are prepared in bulk by specialist manufacturers, packaged in unit dose or other convenient package size and marketed. Typically the marketed compositions are packaged in glass bottles for sale. Such compositions when purchased are transferred shortly prior to use from the container in which purchased to the reservoir from which they are to be administered via a reservoir filling port or other opening of the reservoir.
Hithereto reservoirs of the type used for administration of such composions have not been used by manufacturers of the compositions as a package or container in which to market their product. Likewise samples collected in such apparatus has been transferred to other containers for long term storage. That is partly because the specialized reservoirs are of too costly a construction to be used as storage containers or as packaging but more importantly because storage and handling in commerce imposes requirements different from those of medical administration. In practice compositions of the kind under consideration may be stored for periods as long as 12 months in the package prior to use. The package container must be inert to the content for at least that period and must be able to withstand the rigours of handling and transport without leakage or damage. For commerce the package should be of a size shape and weight which permits economical handling and is of acceptable manufacturing cost. Importantly there must be substantially no water vapour loss which would allow concentrations to alter during storage.
Likewise the packages or containers in which such liquid composit:ons have been marketed have hitherto been unsuitable for dispensation of contents to, or collection of samples from, patients via a tube. That is not only because the container lacks a suitable shape and/or fittings but because the material of which the packaging container was made have either been unsuitable for the construction of specialized reservoirs for medical use or have other disadvantages in practice. Glass reservoirs are dangerous to pressurize and suffer from a number of disadvantages including fragility, high cost, high weight, inflexibility.
The disadvantages of prior art may conveniently be exemplified by reference to enema bags such as used for administration of a barium enema prior to single or double contrast radiography.
A conventional enema bag is an elongate, generally tubular, reservoir having a filling port at one end and provided at the other end with a delivery tube or means such as a spigot for connection with an enema delivery tube whereby the reservoir is placed in communication with a rectal tip adapted for introduction of the reservoir contents into the rectum of a patient.
The enema delivery tube is usually provided with a valve or clamp between the reservoir and the rectal tip. The reservoir filling port is provided with a closure.
For use in double contrast radiography of, for example, the colon an additional requirement is that the bag be capable of being pressurised. After the colon has been filled with the barium enema, the colon is drained leaving a film on the colon wall and air from the bag is usually admitted to inflate the colon. For that purpose the enema bag and filling port closure must be pressure tight. Enema bags made from rubber and stainless steel vessels have been preferred for pressure resistance but are not transparent.
Hitherto compositions for use as a barium enema have been prepared immediately prior to use by dispersing barium sulphate in a required quantity of water or have been purchased as a predispersed suspension of barium sulphate in water. In either case the dispersion is first made up to a required solids content and then admitted from the preparation vessel or storage container via the filling port into the enema bag. As hereinafter used the term "barium enema" refers to a suspension in liquid and not to a dry powder.
As considerable time is required to prepare a suspension from dry powder the use of the predispersed barium enemas is generally most convenient but some adjustment of concentration or viscosity is often desired by the radiographer prior to administration, as dictated by the method of patient preparation or suspected pathology.
Predispersed barium enemas marketed in glass bottles have not avoided the inconvenience of transfer to a flexible enema bag prior to use. It would be desirable to provide an enema bag at sufficiently low cost as to render it disposable and suitable to be pre-packed with a barium suspension.
An object of the invention is to provide an improved container suitable for the storage and/or transport in commerce of a liquid intended to be transferred to a patient via a tube.
A further object of the invention is to provide a container useful in medical procedures which is suitable for transport and/or long term storage of a liquid composition and which is adapted to facilitate dispensation to, or reception from, a patient of the composition via a tube.
A further object of the invention is to provide a reservoir useful in the dispensation to or reception from a patient via a tube of a liquid composition or suspension and which avoids at least some of the disadvantages of the prior art. Desirably the reservoir should be capable of construction at a sufficiently low cost as to be disposable.